216 ALASKAN GLACIER STUDIES
Bay, and Russell Fiord was a feature not observed in previous years. It was heavier near Osier Island on June 12th to 16th than on the 19th and near the sealing camp on June 19th to 22nd than on the 12th. We thought of it at first as possibly due to a great advance and increase of iceberg discharge from'Hubbard or Nunatak Glacier, or both. This was perhaps a contributing cause, but the clearing up of the ice jam, even while we were there, shows that it was not the chief reason. As a matter of fact neither glacier had advanced much, and Nunatak Glacier which moved out the farthest of the two did not supply Nunatak Fiord with many more icebergs on June 17th than during the previous years.
The ice jam seems to be due mainly to a climatic combination. There was an exceptionally heavy snowfall in 1909-10 and a late spring, for photographs show that there was much more snow at sea level in Yakutat Bay on June 11-26,1910, than at the time of Russell's visit on July 3, 1890, or that of the Harriman Expedition on June 19-22, 1899. There was far more than during our previous visits. The local climate was therefore colder, icebergs melted more slowly, and their freezing together at night hindered free floating with the tide. These conditions, combined with a little increase of iceberg discharge, are doubtless responsible for the ice jam of June, 1910. Such a jam may occur, in less accentuated form, every spring. Our previous visits have perhaps been just too late to witness it, though natives have reported heavy ice which interfered with sealing operations just before our arrival in several previous years. There was probably less ice just before our visit in 1910, for a bear hunter and the missionary of Yakutat had each penetrated into Russell Fiord in a smaller and less powerful boat than ours not long before our visit in the middle of June. They encountered less ice than we did.
Since the ice jam formed after these visits and cleared up somewhat while we were there, probably moving outward down the bay, it is thought to be an abnormal occurrence due to such a combination of circumstances as is outlined above.
There seems to have been a similar ice jam in Yakutat Bay in the spring of 1911, as is indicated by the following letter. \
Branch Hydrographic Office,
POBT TOWNSBND, WASH.
April 17,1911. NOTICE TO MABTNERS
Captain McGfllivray of the Am. S. S. "BERTHA" reports that on April 10,1911 in Lat. 59° 38', N. Long., 141° SO' W. passed through a field of drift ice and large bergs. Ship ran 58 miles E. N. E. with ice on all sides as far as 80 miles off shore. Had to stop the ship on. several occasions on account of large bergs floating so close together. Ice was probably blown out of Disenchantment Bay. Large bergs were drifting toward the track of ships passing to the eastward of Cape St. Elias.
A. B. WTCKOBTT, Lieut. U. 8. N.
The latitude and longitude given is off the western edge of Malaspina Glacier and almost directly south of the new Icy Bay (Chapter HI). It is quite possible that these icebergs may have come from there rather than from Disenchantment Bay. As drift ice in sufficient amount to interfere with navigation is exceedingly unusual in this part of the Pacific Ocean the occurrence is well worth attention.
Glacial Sculpture Below Sea Level. Glacial erosion above sea level was studied in our investigation before 1910 and earlier by Russell and Gilbert. Below sea level the form of the bay and fiord are revealed by soundings, which were first carried on systematically